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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proto-oncogenes were studied by Southern blotting in 12 patients with chronic myelogenous leukemia in blast crisis (CML). Cytogenetically, all cases had Philadelphia (Ph1) chromosome and 4 had additional chromosomal abnormalities including +8, +19, i(17q), double Ph1. The bcr gene was rearranged in all cases and the region of breakage points were located in the 5.8 kb Bgl II-Bam HI fragment of bcr. In a case with double Ph1 the breakage points of bcr were thought to be different from each other. We analyzed other proto-oncogenes (N-ras, H-ras, c-myc and myb) by Southern blotting, but did not find any abnormalities.
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PMID:Southern blot analysis of Bcr, N-ras, H-ras, c-myc and myb proto-oncogenes in blast crisis of chronic myelogenous leukemia. 274 49

We have determined the prevalence of amplification and rearrangements for c-myc, c-myb, c-mos, bcr, c-abl, c-Ha-ras-1, c-N-ras, and c-K-ras-2 in a total of 51 cases of human leukaemia (19 patients with AML, 13 cases with CML, 14 cases with ALL, and 5 cases with CLL). Amplifications at a level of more than 2 two copies per haploid genome are apparently very rare and were found only once for c-myb in a c-ALL patient. Oncogene rearrangements were not found except for bcr, which was rearranged in all cases of CML, and 5 cases of ALL studied. Restriction fragment lengths polymorphisms (RFLPs) were also analysed. A previously described rare 5 kb EcoRI allele at the c-mos locus was absent in our patients. Rare alleles at the c-Ha-ras-1 locus were found to be significantly more prevalent in our patients than in a control group. Transfection experiments revealed no dominant transforming oncogenes in the tumour DNA of 3 patients carrying such rare alleles.
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PMID:Oncogene amplifications, rearrangements, and restriction fragment length polymorphisms in human leukaemia. 288 56

We describe here a patient with Ph'-positive chronic myelogenous leukemia (CML) who developed a Ph'-negative blastic crisis. The blast DNA was analyzed on two different occasions, at the beginning of the blastic phase and at the end, shortly before the patient's death. Although cells from both samples had no Ph' chromosome marker (not even a masked one) we could detect a rearrangement of the bcr gene in the second DNA sample, using a '3'-bcr' probe. The same probe and a '5'-bcr' probe failed to detect any rearranged band in the first DNA sample. No rearrangement was identified at the c-myc and N-ras loci, while a slight c-myc amplification was evident in both DNA samples tested.
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PMID:Molecular analysis of the bcr rearrangement in a case of Ph'-negative blastic crisis of Ph'-positive chronic myelogenous leukemia. 291 93

High-molecular weight DNAs of fresh bone marrow cells from 32 patients with fresh leukemia were assayed for the presence of transmissible activated transforming genes by a DNA-mediated gene transfer technique using NIH/3T3 cells. DNAs of bone marrow cells from four of the 32 patients induced transformation of NIH/3T3 cells. Two of the four cases, a chronic myelogenous leukemia and an acute lymphocytic leukemia, contained activated N-ras oncogenes. Molecular cloning and nucleotide sequence analysis revealed that the lesion responsible for the transforming activity was localized to a single nucleotide transition from guanine to thymine in codon 12 of the predicted protein in each of the two cases. These observations indicate that activation of N-ras oncogenes is independent of the specific stage of cell differentiation or the leukemia phenotype. The other two transforming genes associated with an acute myelogenous leukemia and an acute lymphocytic leukemia showed homology neither with members of the ras gene family nor with the human Blym-1 gene. Thus, the NIH/3T3 transfection assay frequently detects activated N-ras oncogenes in human leukemias, while other transforming genes, distinct from the ras gene family, can be detected in some leukemias by the transfection assay.
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PMID:Transforming genes in human leukemia cells. 299 10

To examine whether determination of (1) the copynumber or restriction pattern of certain oncogenes or (2) the mutational activation of the N-ras gene might contribute to the risk classification of acute lymphoblastic leukemia of childhood (ALL), we investigated DNA isolated from lymphoblasts of untreated patients. Restriction enzyme analysis of cellular oncogenes was performed on DNA of 25 patients. No rearrangements could be demonstrated within or near the genes c-myc, c-myb, c-abl, bcr, c-Ki-ras, and N-ras. No amplifications of these genes nor of N-myc or c-Ha-ras were present. Eight of 21 patients were heterozygote for "rare" Ha-ras allelic restriction fragments that have been associated with an increased risk of developing a malignancy. These patients were clinically indistinguishable from patients lacking these fragments. The breakpoint cluster region (bcr) that is rearranged in all patients with Philadelphia chromosome positive chronic myeloid leukemia, was normal in all cases, including at least one patient with Philadelphia chromosome positive ALL. A 2.8 kb HindIII fragment of a hitherto unknown gene or pseudogene related to v-myb probably derives from the Y chromosome. Nineteen patients were examined for point mutations in the N-ras gene, using a novel synthetic oligonucleotide hybridization assay. In two patients activating point mutations were present, both in positions 1 of the 12th codon. Both patients were somewhat older than the others (16 and 11 years), had L2 morphology, and were shown to have high growth fractions of tumor in their bone marrow.
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PMID:Absence of oncogene amplifications and occasional activation of N-ras in lymphoblastic leukemia of childhood. 301 Nov 51

Acute myelocytic leukemias (AML) are characterized by a remarkably high incidence (approximately 30%) of point mutations affecting codons 12, 13, or 61 within ras genes. A predominant involvement of N-ras sequences has been established. Neither Philadelphia chromosome-positive chronic myelocytic leukemia nor other chronic myeloproliferative disorders show a similar frequency. However, a proportion of myelodysplastic syndromes, namely, the chronic myelomonocytic subtype (CMML) also show this molecular feature. The following is a brief discussion of the possible biologic and clinical implications of these observations.
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PMID:Mutations in ras genes in myelocytic leukemias and myelodysplastic syndromes. 306 84

The expression of c-abl, c-sis, c-myc and N-ras oncogenes was examined in 2 lymphoblastoid cell lines, one with Ph1 (PB-1049) and the other without Ph1 (LN-1049), both established from a patient with chronic myelogenous leukemia (CML), and in a Ph1-positive cell line (PB-1049-T) derived from a tumor formed after transplantation of PB-1049 cells in a nude mouse with reference to their tumorigenic potential in nude mice. The normal transcripts of c-abl were detected in all 3 lymphoblastoid cell lines. Although in situ hybridization of v-abl proved, and restriction endonuclease analyses of the bcr region strongly indicated the occurrence of bcr-abl rearrangement in PB-1049 and PB-1049-T, we could not obtain any evidence for the expression of the hybrid bcr-abl mRNA. These results indicate that the Ph1 translocation does not ensure the production of the hybrid bcr-abl mRNA, and that the expression of hybrid bcr-abl gene is not essential for the maintenance of tumorigenicity of these cell lines. Expression of c-sis was not detected in any of the cell lines examined, whereas the expression of c-myc was uniformly higher in the 3 cell lines than in normal control cells. The levels of N-ras expression varied considerably, probably in parallel with the changes in tumorigenicity of the cell lines. N-ras expression in the PB-1049 and PB-1049-T cell lines was higher than that in the LN-1049 line when they retained tumorigenic potential, but it fell to the level of LN-1049 with loss or decline of tumorigenicity.
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PMID:Absence of the hybrid bcr-abl mRNA in Ph1-positive B lymphoblastoid cell lines established from a patient with chronic myelogenous leukemia. 312 21

Remarkable chromosome abnormalities were observed in bone marrow cells from a woman with chronic myelocytic leukemia and atypical tuberculosis due to Mycobacterium avium-intracellulare infection. Four chromosome breaks occurred at bands 1p13, 1q32, 11p15, and 22q11. These breaks resulted in a complex Philadelphia (Ph) translocation between chromosomes #1, #11, and #22 and in an inversion of chromosome #1. Oncogenes on these chromosomes include N-ras and c-sk on chromosome #1, c-H-ras on chromosome #11, and c-sis on chromosome #22. Complex chromosome rearrangements may facilitate multiple oncogene changes, thereby permitting several steps in cancer development to occur simultaneously.
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PMID:The Philadelphia (Ph) chromosome in leukemia. III. Complex Ph translocation plus inversion in chronic myelocytic leukemia. 385 75

A new Ph1-positive leukemic cell line (MC3) expressing the P210bcr/abl oncoprotein was established from a patient with CML in blast crisis. The MC3 cells showed the trilineage phenotype of myeloid, lymphoid (CD19) and megakaryocytoid lineages, and had a proliferative response to rhIL-1 and rhIL-3 in the serum-free culture. These results and the expression of CD34 indicated that the MC3 cells have characteristics of hematopoietic progenitor cells. Recently, it has been documented that alterations of the p53 gene in leukemic cells are frequently detected during the blast crisis of CML. The MC3 cells contained the altered p53 gene. In addition, the original leukemic cells showed the point-mutational activation of the N-ras gene and an additional chromosomal abnormality inv(3q), but the MC3 cells contained no such abnormalities, indicating that not all of the original leukemic cells had these abnormalities. Thus, the MC3 cell line may provide several insights into investigations of the blast crisis in CML as well as hematopoietic progenitor cells.
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PMID:Establishment and characterization of a new Ph1-positive chronic myeloid leukemia cell line MC3 with trilineage phenotype and an altered p53 gene. 778 56

Minute alterations of the p53 tumor suppressor gene and N-ras oncogene were investigated in 106 samples for the p53 gene and 23 samples for the N-ras gene obtained from patients with various types of hematologic malignancies using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and direct nucleotide sequencing. Mobility shifts suggesting sequence alteration were observed in 9 cases (8.5%) in exons 5 through 8 containing evolutionarily highly conserved regions of the p53 gene by PCR-SSCP; missense point mutations in 3 cases (1 acute myelogenous leukemia (AML), 1 chronic myelogenous leukemia (CML) in the accelerated phase, and 1 CML in the blast crisis), silent point mutation in 1 case (malignant lymphoma), and frame shift mutations due to insertions and deletions causing stop codons in 3 cases (1 AML, 1 CML in the chronic phase and 1 acute lymphoblastic leukemia (ALL)). p53 gene alterations did not always cluster within evolutionarily highly conserved regions, and there were various base change forms in cases with p53 point mutations. p53 mutations were detected in 2 cases out of 4 cases with 17 monosomy. There was no case with p53 gene alteration in myelodysplastic syndrome (MDS) cases. Mobility shifts suggesting sequence alteration were observed in 5 cases (22%) in exon 1 and 2 of the N-ras gene by PCR-SSCP. 3 cases (1 MDS, 1 MDS overt AML and 1 ALL) were detected to contain missense point mutations. However, simultaneous mutations in both the genes were detected in only 2 cases out of 23, thereby indicating infrequent occurrence of concomitant mutation of both the genes in hematologic malignancies. Alterations of the p53 and the N-ras genes are involved in the tumorigenesis, progression and prognosis of at least some cases of hematologic malignancies, in spite that they are relatively infrequent.
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PMID:[Molecular study on minute alterations of the p53 and the N-ras genes in hematologic malignancies]. 792 79


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